Many new and existing golf courses have narrowed their fairways and expanded their rough areas on either side of the fairways. Roughs require less care than fairways, so narrowing the fairways allows golf course operators to lower their maintenance costs. For example, irrigation requirements may be reduced if only the fairways are watered. If grasses in the roughs are allowed to grow longer, those non-irrigated areas are less brown. Trees and other aesthetic features may be located in the roughs, because roots and shade can inhibit turf growth in the fairways.
However, golf course roughs still must be maintained regularly using grass mowing machines that can mow the vegetation at an acceptable length and appearance. Equipment for mowing golf course roughs typically includes a traction vehicle carrying three or more rotary cutting decks, each rotary cutting deck mounted on the end of a lift arm extending from the traction vehicle. Carrying the rotary cutting decks with lift arms extending from the front or sides of the traction vehicle is necessary and desirable, instead of towing the rotary cutting decks behind the vehicle, because it is necessary for the mower to provide close trims next to trees, bunkers or other hazards. Each lift arm also may be used to move a rotary cutting deck between a mowing position and a transport position. The mounting devices also should allow for pitch (front to back pivoting) and yaw (side-to-side pivoting) of the rotary cutting decks.
Traction vehicles carrying several rotary cutting decks may travel at speeds of 6 to 8 miles per hour when mowing golf course roughs. The traction vehicle's weight may be in excess of 2000 pounds. Each rotary cutting deck may be subject to shocks from impacts against the ground surface or objects during mowing. To withstand the rigorous mowing conditions, rotary cutting decks typically are made of thick sheet steel, such as 7 gage or 10 gage sheet steel. Each rotary cutting deck may have a diameter between about 18 inches and 27 inches, weigh at least 120 pounds, and may have a cutting blade rotated by a hydraulic or electric motor.
Rotary cutting decks for mowing golf course roughs typically include a rear discharge opening. Grass clippings may exit the deck through the rear discharge opening such that the clippings may lie on top of the turf. If the deck encounters heavy or thick grass or vegetation, the deck may become clogged and the cut clippings may be deposited in clumps instead of dispersing evenly through the discharge opening. A rotary cutting deck with a rear discharge opening is needed that reduces the possibility that the deck may become clogged, and that disperses grass clippings evenly and not in clumps.
Rotary cutting decks also should provide high cut quality, even on golf course roughs. If grass clippings collect under the deck, they may block the rotary cutting blade from cutting all of the grass at the specified height. A rotary cutting deck with a rear discharge opening is needed that provides high cut quality.
Golf course operators have attempted to reduce noise generated by mowing equipment. A rotary cutting deck is needed that operates with low noise. In the past, rear discharge openings have been designed by cutting large rear openings in the back wall of the deck. For example, U.S. Pat. No. 6,470,663 relates to a rear discharge opening formed by a cut-away portion of a peripheral wall of the cutting chamber. The large rear opening may help prevent the deck from clogging, but also may result in poor dispersion of clippings. Additionally, a large rear opening may require a bolt on bar or a long discharge chute to meet the foot probe test for safety requirements. A rotary cutting deck is needed that meets safety requirements and minimizes risk of injury to operators or bystanders.